Ординатура / Офтальмология / Английские материалы / Quick Reference Dictionary of Eyecare Terminology 4th edition_Ledford, Hoffman_2005

54 corneal topography/corticosteroids

corneal topography: Technique in which an image projected onto the cornea is analyzed by a computer to obtain a representation of the shape of the corneal surface and thus an indication of its refractive power; also called corneal mapping and videokeratography.

corneal transplant: See keratoplasty.

corneal ulcer: Loss of tissue from the surface of the cornea due to a disease process, often an infection.

corneoscleral: Of or involving the cornea and sclera. corneoscleral junction or spur: Another term for scleral

spur.

corrected visual acuity (Vacc): Visual acuity measured with the patient’s current corrective lenses in place (ie, no attempt is made to further improve vision optically); compare best corrected visual acuity and uncorrected visual acuity.

correction: In ophthalmic usage, spectacles or contact lenses prescribed to counteract myopia, hyperopia, astigmatism, or any other ametropia.

correspondence: See retinal correspondence.

cortex: In ophthalmic usage, the soft outer portion of the crystalline lens of the eye; visual c. area of the occipital lobe of the brain that receives visual input.

cortical attachments: Areas in which the nucleus and cortex of the crystalline lens adhere together.

corticosteroids: Substances used to reduce inflammation; topical steroid drugs used in ophthalmology include prednisone, dexamethasone, and fluorometholone; topical steroids are sometimes combined with antibiotics to fight infection as well; side effects in the eye can include increased intraocular pressure; also called steroids; compare nonsteroidal anti-inflammatory drugs.

cotton-wool spots (CWS): Small areas of the retinal nerve fiber layer that have lost their blood supply and become wispy white spots with no clear borders; also called soft exudates, although technically they are not exudates; see also retinal exudates.

couching: Obsolete treatment for cataract in which the whole lens of the eye was detached and pushed out of the visual axis, usually accomplished with a needle inserted into the anterior chamber of the eye.

count-finger vision: Very low level of visual acuity in which no greater detail can be perceived than the number of fingers held before the eyes; see also handmotion vision, light perception vision, no light perception vision, and visual acuity.

coupling agent: In ophthalmology, a clear, thick substance used to cushion a lens (eg, goniolens) or ultrasound probe (eg, B-scan) where it contacts ocular tissues; in ultrasound it also acts to facilitate transmission.

cover test: Test to determine the presence of phoria or tropia; there are several types but all involve having the subject fixate on a target while the examiner covers an eye and observes for any movement; if there is no movement, the patient is orthophoric; alternate c.t. or cross c.t. cover test performed by quickly moving the occluder from one eye to the other so that there is no time for binocular fixation to occur; used to detect the presence and direction of deviation but cannot distinguish between phoria and tropia; cover-uncover test cover test performed by covering then uncovering one eye; used to distinguish between tropia and phoria and to determine the direction of deviation; prism and alternate c.t. (PACT) or prism and c.t. use of prisms in conjunction with alternate cover test in order to measure the amount of deviation.

56 CPT codes/cryo-

CPT (Current Procedural Terminology) codes: System of designating medical procedures and services, developed by the American Medical Association to facilitate billing and care review by providing uniformity in communication.

cranial nerve(s) (CN): Twelve pairs of nerves (motor, sensory, and mixed) that originate in the brain, designated both by Roman numerals (I to XII) and names; six of them affect vision either directly or indirectly; the optic nerve is CN II; see Appendix 5.

crazing: In ophthalmic usage, the appearance of a network of fine lines or cracks on a lens, most often a contact lens.

cribrosa: See lamina cribrosa.

cross cylinder: Lens comprised of two cylindrical components of the same power, one plus and one minus, superimposed at right angles to each other, used to measure astigmatism; also called Jackson cross cylinder lens.

cross fixation: Condition in which the left eye becomes dominant in gaze toward the extreme right and the right eye becomes dominant in gaze toward the extreme left.

crossed diplopia: Another term for heteronymous diplopia.

crossing changes: Another term for AV crossing.

cryo-: Combining form meaning cold, used in medical terminology to describe treatments or surgical procedures involving very low temperatures (usually several hundred degrees below zero).

cryoextraction/culture 57

cryoextraction: Technique of intracapsular cataract extraction in which the lens capsule and its contents are frozen to the tip of a surgical instrument (ie, cryoprobe) and removed as a unit; now largely abandoned in the United States but still performed by many surgeons around the world; see also cataract extraction, extracapsular cataract extraction, intracapsular cataract extraction, and phacoemulsification.

cryopexy: Surgical procedure that attempts to fix a tissue into place by application of extreme cold (most commonly in ophthalmic usage, a detached retina against the choroid).

cryophake: Instrument used in cataract cryoextraction. cryoprobe: General term for instrument used in

cryosurgery. cryoretinopexy: See retinopexy.

cryosurgery or cryotherapy: General term for application of extreme cold to tissue.

crystalline lens: Proper term for the natural lens of the eye (usually called simply the lens), consisting of a soft outer cortex and hard nucleus in the center; use of the full term crystalline lens is helpful as a distinction from manufactured lenses for vision correction.

cul de sac: General anatomic term for a sac with only one opening (from French for “bottom of the bag”); in ophthalmic usage, the sac formed by the bulbar and palpebral conjunctivae; also called the fornix; see also conjunctiva.

culture: 1. A method of growing bacteria and fungi in the laboratory; c. medium a substance formulated for growing microorganisms in the lab; 2. technique whereby a sample of infected tissue or exudate is placed into growth medium.

58 cup/cyclocryotherapy

cup: General term referring to a depression; “bean pot” c. glaucomatous cup where there is no visible neural rim; glaucomatous c. see cupping; physiologic c. in ophthalmic usage, the normal slight depression at the center of the optic nerve.

cup-to-disk ratio (c/d): Measure of the proportion of damaged area (ie, cup) to visually functional area (ie, disk) of the retina, representing the relative progression of glaucomatous damage; see also glaucoma.

cupping: Sign of glaucomatous damage in which the optic disk is affected by an area of increasing concavity, representing nonfunctioning retinal cells.

customized ablation: General term in refractive surgery to describe an excimer laser procedure that has been modified to fit the needs of a particular patient, most often referring to a highly individualized pattern of laser treatment designed to correct not only myopia, hyperopia, and astigmatism, but also higher-order optical aberrations; see also wavefront-guided ablation.

cyanolabe: Visual pigment present in the “blue” retinal cones that absorb light in the blue frequencies (around 440 nm); one of three visual pigments: see also chlorolabe, erythrolabe, and trichromatism.

cycl-, -o-: Combining form meaning circle or ring; in ophthalmic usage, the iris and/or ciliary body.

cyclitic membrane: Formation of fibrous tissue in the anterior part of the vitreous body as a result of severe inflammation of the ciliary body.

cyclitis: Inflammation of the ciliary body; also called intermediate uveitis; see uveitis.

cyclocryotherapy: Application of very low temperatures to the ciliary body performed in an attempt to decrease the production of aqueous fluid by the ciliary processes as a treatment for glaucoma.

cyclodestruction/cylinder 59

cyclodestruction: General term for glaucoma surgical procedures that destroy portions of the ciliary body (as with extreme cold, laser energy, or other means) in order to decrease the production of aqueous fluid.

cyclodialysis: Largely abandoned glaucoma surgical procedure in which the root of the iris is detached from the ciliary body so that aqueous fluid may pass more easily out of the anterior chamber and thus reduce intraocular pressure.

cyclodialysis cleft: Detachment of the ciliary body, often from trauma, causing hypotony.

cycloduction: Rotation of one eye around its visual axis (anterior-posterior pole); also called cyclotorsion; compare cyclovergence.

cycloplegia: Paralysis of the ciliary muscle in which the eye does not accommodate in response to the usual stimuli.

cycloplegic: In ophthalmology, a drug that causes cycloplegia (eg, tropicamide, cyclopentalate, etc).

cyclotorsion: Another term for cycloduction. cyclovergence: Rotation of both eyes around their visual

axes (anterior-posterior poles); if the right eye rotates clockwise, the left eye rotates counterclockwise and vice versa; compare cycloduction.

cylinder (cyl): 1. In optics, a lens that is flat along one axis and circularly curved along the perpendicular axis or the property of a lens that is relatively flat along one axis and more curved along the perpendicular axis; compare sphere; minus c. refracting surface of a lens in which the lens material is fashioned into the concave reverse of a cylindrical shape (ie, as if a cylinder had been carved out of the lens and discarded); plus c. refracting surface of a lens in which the lens material is fashioned into the convex shape of a cylinder; 2. in refraction, the component of refractive error that can be corrected with a cylindrical lens (roughly synonymous with astigmatism).

60 cyst/cytomegalovirus retinitis

cyst: A blister-like fluidor air-filled lesion, generally benign.

cystoid macular edema (CME): Swelling of the central focusing area of the retina, typically as a result of trauma or as a complication of ophthalmic surgery.

cystotome: Surgical instrument for cutting a sac; most often in ophthalmic usage, instrument for cutting into the lens capsule.

cytomegalovirus (CMV) retinitis: See retinitis.

D

dacry-, -o-: Combining form meaning tear fluid; see also combining forms beginning with lacri-.

dacryocyst: Another term for nasolacrimal sac. dacryocystitis: Inflammation of the nasolacrimal sac,

usually because of an infection and blocked nasolacrimal duct.

dacryocystorhinostomy (DCR): Procedure in which an opening between the dacryocyst and the nasal passage is created or reopened.

dacryostenosis: Blockage of the nasolacrimal passages. dark adaptation: See adaptation.

dark adaptometry: Measurement of the eye's ability to dark-adapt over time; used in cases of night vision problems; see also Goldmann-Weekers dark adaptometer; d.a. curve plot line showing patient's responses to dark adaptometry testing.

dark trough: In electro-oculography, the response with the least width during the dark-adapted phase of testing; compare light peak; see also Arden ratio.

datum line: Another term for “C” measurement. debride: To remove foreign material and/or dead tissue

from a wound.

decentration: General term for misalignment; in ophthalmic usage, usually referring to displacement of a lens (spectacle, contact, or intraocular) or prism out of the visual axis.

decongestant: Substance used to reduce swelling and blood accumulation in an area; in ophthalmic usage, a drug that reduces ocular redness.

62 defocus/depth perception

defocus: In optics, the lower-order optical aberration that focuses an image too strongly or weakly, resulting in myopia or hyperopia, respectively.

degenerative cataract: See cataract. degenerative myopia: See myopia.

degree: 1. In history taking, the extent to which a problem exists; 2. in strabismus, a measurement that indicates the amount of crossing; 1 degree equals approximately 2 prism diopters.

dehiscence: General medical term for a splitting open of tissue, often as a result of fibrosis in the course of healing of a traumatic or surgical wound; in ophthalmic usage, typically referring to splitting of retinal tissue or breakage of the lens zonular fibers.

dellen: See corneal dellen.

dendrite: Short filaments of a nerve cell body that receive impulses from other nerve cells (via the axons of those cells); see also axon and synapse.

dendritic: Describing a tree-like shape; used often in ophthalmic terminology to describe lesions on the cornea that have a branched appearance (eg, as in dendritic keratitis).

deorsumversion: Downward turning of both eyes; compare supraversion.

depression: Turning down of the eye; also called infraduction; compare elevation.

depth of field: Space in front of and behind an object of regard in which other objects can also be clearly seen; the depth of field is typically very shallow for nearby objects and deeper for very distant objects; typically of consideration in photography.

depth perception: The ability to discern the relative distance of objects within the field of view, made possible by the varying degrees of convergence necessary to focus upon objects at varying distances from the observer; present even when binocular vision and fusion are not achieved; compare stereopsis.

dermatochalasis/deviation 63

dermatochalasis: General term referring to loose, baggy skin; see blepharochalasis.

desaturated 15 panel: Color matching test that employs 15 very pale colored caps that the patient arranges; results differentiate between protan, deutan, and tritan even if the defect is subtle; compare FarnsworthMunsell D-15; also called Lanthony desaturated D-15 panel.

Descemet’s membrane: Inner tissue layer of the cornea to which the corneal endothelium adheres.

detachment: Separation of tissue layers that are normally attached; in ophthalmic usage, most commonly referring to the retina or choroid; see also retinal detachment and vitreous detachment.

deutan: Color vision defect involving the green color mechanism and linked to the X chromosome; this is the most common form of color blindness.

deuteranomaly: Partial impairment of the green color mechanism resulting in poor red/green discrimination, although red is normally vivid.

deuteranopia, -opsia: Severe lack of the green color mechanism; red and yellow-green both look orange; red-orange, orange, and yellow are all the same strong red-orange color; magenta and green are gray tones; blue-green to purple are various confusing shades of blue.

deviation: In ophthalmic usage, a turning of the eye from the point of fixation; convergent d. see esotropia; dissociated vertical d. deviation in which either eye drifts upward when it is occluded; divergent d. another term for exotropia; primary d. where an ocular muscle is paralyzed, the deviation that exists when the nonparalyzed eye is fixating; secondary d. where an ocular muscle is paralyzed, the deviation that exists when the affected eye is forced to fixate (typically the primary d. is less than the secondary d.); skew d. a vertical strabismus caused by an anomaly in the brainstem or cerebellum.